Cleaning paving slabs

Nigzcurran · 10-05-2020 02:23PM #1

Hi I’m wondering is it possible to get these back clean and new looking, the grey ones are ok but the pink are looking terrible, it looks like some kind of mould maybe? I’ve power washed them already. they are around 10 years old, thanks

Alun · 10-05-2020 02:54PM

It's called black spot, caused by lichens which are a symbiotic combination of algae and fungi. The algal part is mainly on the surface and can be easily got rid off by power washing, but the fungal part has "roots" called hyphae which go deep into the stone and are much more difficult to get rid of.

Here's more than you'll ever need to know about how to try to get rid of them ...

https://www.pavingexpert.com/maintain_03

Nigzcurran · 10-05-2020 03:33PM

Thanks yep plenty of info and that’s exactly what’s on my slabs, they are pretty old and I’m not sure if they are worth spending much money or hard work on, I might try it on one or two slabs to see how it goes

rob316 · 10-05-2020 10:27PM

Chloras. You can get it in your local co op store, excellent stuff.

JMR · 10-05-2020 11:19PM

Recent thread related to this

https://touch.boards.ie/thread/2058069806/1

Sodium hypochlorite worked somewhat for me

Nigzcurran · 10-05-2020 11:34PM

Cheers it’s definitely worth a shot, that before and after pic in the linked thread are amazing

Cleaning paving slabs

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